Awhile back we covered an invisibility cloak that works on the infrared spectrum of light. Now researchers at Caltech and the Center for Nanophotonics in Amsterdam have created the first metamaterial with a negative index of refraction for most wavelengths of visible light. It can’t bend away violet light, so anything cloaked in the material might appear purple. I still want one so I can be Grimace for Halloween. Sure, I could buy purple fabric, but why do that when I could use a “two-dimensional array of coaxial waveguides arranged in a hexagonal configuration […] composed of two layers of silver sandwiching a gallium-phosphorus insulator”? [ArsTechnica] That’s just science.

This new type of negative-index metamaterial (NIM) […] is simpler than previous NIMs—requiring only a single functional layer—and yet more versatile, in that it can handle light with any polarization over a broad range of incident angles. […] “By engineering a metamaterial with such properties, we are opening the door to such unusual—but potentially useful—phenomena as superlensing (high-resolution imaging past the diffraction limit), invisibility cloaking, and the synthesis of materials index-matched to air, for potential enhancement of light collection in solar cells,” says Harry Atwater. [Physorg]

All those uses are awesome, but let’s be honest: the best application of all is to make a trippy purple version of Charlie Day’s green man suit.